CN113939994B

CN113939994B - Heating control method and device, oil pump motor and heat exchange system

Info

Publication number: CN113939994B
Application number: CN202180002903.1A
Authority: CN
Inventors: 石超杰; 额尔和木巴亚尔; 毋超强; 王少华; 谢小威
Original assignee: Huawei Digital Power Technologies Co Ltd
Current assignee: Huawei Digital Power Technologies Co Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2024-05-14
Anticipated expiration: 2041-06-29
Also published as: US20240133398A1; EP4340210A1; CN113939994A; WO2023272527A1

Abstract

The embodiment of the application provides a heating control method, a heating control device, an oil pump and a heat exchange system, wherein the method comprises the following steps: in a cold state, injecting heating current into the oil pump motor; when the oil pump motor is not started, the torque generated by the heating current is zero; after the oil pump motor is started, the heating power of the heating current is larger than that of the energy-saving current, and the energy-saving current is a current which can enable the first motor to reach a target operation condition when the oil temperature is larger than a preset temperature threshold value.

Description

Heating control method and device, oil pump motor and heat exchange system

Technical Field

The application relates to the technical field of control, in particular to a heating control method and device, an oil pump motor and a heat exchange system.

Background

When the temperature of the motor operating environment is low, the viscosity of the oil in the motor is high under the low-temperature condition, so that the flow rate of the oil in the motor is very slow, and the motor is difficult to work normally.

At present, a technical solution capable of heating oil in a motor faster is needed.

Disclosure of Invention

The embodiment of the application provides a heating control method and a related device, which can rapidly heat oil in a vicinity of a motor.

In a first aspect, an embodiment of the present application provides a heating control method, including:

When the cold condition is met, heating current is injected into the first motor;

Wherein the first motor is an oil pump motor in an oil pump; the heating current satisfies the following control objectives: when the first motor is in an un-started state, the heating current is zero torque current, and the torque which can be generated by the zero torque current is zero; and/or when the first motor is in a starting state, the heating current is a heating current, and the heating power of the heating current is larger than that of the energy-saving current, wherein the energy-saving current is a current capable of enabling the first motor to reach a target operation working condition when the oil temperature is larger than a preset temperature threshold.

By adopting the mode, the first motor can be utilized to self-heat, so that the oil in the adjacent area of the first motor can be quickly heated, and the first motor can be enabled to enter a high-speed rotation state as soon as possible.

In one possible implementation, the cold condition includes:

The temperature of the adjacent area of the first motor is lower than the preset temperature threshold; or alternatively

The rotating speed of the first motor working based on the energy-saving current is smaller than a preset rotating speed threshold, wherein the preset rotating speed threshold is the target rotating speed in the target operating condition.

In one possible implementation, the cold condition includes:

The operation working condition of the first motor is a low-loss working condition, wherein the loss heating power of the low-loss working condition is smaller than the expected loss heating power threshold; or alternatively

The loss heating power corresponding to the operation condition of the first motor is smaller than an expected loss heating power threshold;

the expected loss heating power is used for enabling the first motor to raise the oil temperature to the preset temperature threshold value in preset time.

In one possible implementation, the method further includes:

And when the cold state condition is not met, injecting the energy-saving current into the first motor.

In one possible implementation, the energy-saving current is a current for enabling the first motor to reach the target operation condition and meet a condition of smaller amplitude, or the energy-saving current is a current for enabling the first motor to reach the target operation condition and meet a condition of complete machine mechanical energy conversion energy efficiency.

In one possible implementation, the heating current is a first heating current or a second heating current;

Wherein the total power of the first heating current is equal to the total power of the energy-saving current, and the proportion of the heating power of the first heating current to the total power of the first heating current is larger than the proportion of the heating power of the energy-saving current to the total power of the energy-saving current;

the proportion of the heating power of the second heating current to the total power of the second heating current is equal to the proportion of the heating power of the second heating current to the total power of the second heating current, and the total power of the second heating current is larger than the total power of the energy-saving current.

The amplitude of the integrated vector current corresponding to the first heating current in the dq rotating coordinate system is equal to the amplitude of the integrated vector current corresponding to the energy-saving current, and the torque which can be generated by the second heating current is smaller than the torque which can be generated by the energy-saving current;

The torque which can be generated by the first heating current is equal to the torque which can be generated by the energy-saving current, and the amplitude of the integrated vector current corresponding to the first heating current in the dq rotating coordinate system is larger than that of the integrated vector current corresponding to the energy-saving current.

In one possible implementation manner, the injecting the heating current into the first motor when the cold condition is satisfied includes:

Injecting the first heating current into the first motor when the first motor is in a locked-rotor state;

When the first motor is in a locked-rotor state, the first motor is in a starting state, and the rotating speed which can be achieved by the first motor based on the energy-saving current is smaller than or equal to a cold state rotating speed threshold value; the cold state rotating speed threshold value is 0 or the rotating speed which can be reached by the first motor when the oil temperature is equal to the cold state temperature threshold value; the cold state temperature threshold is less than or equal to the preset temperature threshold.

injecting the second heating current into the first motor when the first motor is in a low-speed state;

When the first motor is in a low-speed state, the first motor is in a starting state, and the rotating speed which can be achieved by the first motor based on the energy-saving current is smaller than a high-speed state rotating speed threshold value; the high-speed state rotating speed threshold is a rotating speed which can be reached by the first motor when the oil temperature is greater than or equal to a high-speed state temperature threshold, and the high-speed state temperature threshold is greater than the cold state temperature threshold.

In one possible implementation, the first motor is an SPM motor or an IPM motor;

The direct-axis current of the corresponding integrated vector current of the first heating current in the dq rotating coordinate system is not 0, and the quadrature-axis current is 0.

In one possible implementation, the first motor is an SPM motor;

the corresponding comprehensive vector current of the second heating current in the dq rotating coordinate system is the second vector current; the comprehensive vector current corresponding to the energy-saving current in the dq rotating coordinate system is the energy-saving vector current;

The direct-axis current of the second vector current is equal to the direct-axis current of the energy-saving vector current, and the amplitude of the second vector current is equal to the maximum amplitude supported by the first motor.

In one possible implementation, the first electric machine is an IPM machine;

The energy-saving vector current is the vector current with the minimum amplitude capable of generating the target torque;

the second vector current is a vector current capable of generating a target torque and having a magnitude greater than the energy saving vector current,

The amplitude of the second vector current is smaller than or equal to the maximum amplitude supported by the first motor.

In one possible implementation manner, the integrated vector current corresponding to the first heating current in the dq rotating coordinate system is a first vector current; the first vector current satisfies the following control objectives:

The included angle between the first vector current and the d axis is 0, and the through-flow mode of the zero-torque vector current is as follows: a communication mode;

Wherein the alternating current pattern represents a change in magnitude of the first vector current over time.

In one possible implementation manner, in the dq rotation coordinate system, the corresponding integrated vector current of the second heating current in the dq rotation coordinate system is a second vector current; the second vector current satisfies any one of the following control targets:

the through-flow mode of the second vector current is a direct-current mode, and the included angle between the second vector current and the d-axis changes along with time; or alternatively

The through-flow mode of the second vector current is an alternating-current mode;

wherein the DC mode indicates that the amplitude of the second vector current does not change with time, and the AC mode indicates that the amplitude of the second vector current changes with time.

In one possible implementation manner, the corresponding integrated vector current of the zero torque current in the dq rotation coordinate system is zero torque vector current; the zero torque vector current meets the following control targets:

The included angle between the zero torque vector current and the d axis is 0, and the through-flow mode of the zero torque vector current is as follows: a communication mode;

Wherein the ac mode represents that the magnitude of the zero torque vector current changes with time.

In one possible implementation, the first motor includes a motor cavity in communication with an oil delivery line; the motor cavity is used for accommodating a stator and a rotor of the first motor; an air gap between a stator and a rotor of the first motor is communicated with the oil pipeline;

When the oil pump motor works, oil is filled in the motor cavity, and the rotor is in contact with the oil in the motor cavity.

In one possible implementation, the integrated vector current corresponding to the heating current in the dq coordinate system may satisfy any one of the following control objectives:

The through-flow mode is a direct-current mode, and the included angle between the comprehensive vector current corresponding to the heating current and the d-axis changes along with time; or alternatively

The through-current mode is an alternating-current mode without direct-current bias;

the through-current mode is an alternating-current mode with direct-current bias.

In one possible implementation, before injecting the heating current into the first motor, the method includes:

acquiring a starting instruction of a second motor; wherein the second motor is an oil-cooled motor; the first motor is used for driving cooling oil to flow to the second motor through an oil pipeline;

after the obtaining the start instruction of the second motor, the method further includes:

Starting the second motor;

controlling the second motor to operate in a low-loss mode;

The loss heating power of the operation working condition of the second motor when the second motor operates in the low-loss mode is smaller than a cold heat dissipation power threshold; the cold heat dissipation power threshold is determined according to a cold rotation speed threshold, wherein the cold rotation speed threshold is the rotation speed which can be reached by the first motor when the oil temperature reaches the cold temperature threshold, and the cold rotation speed threshold is smaller than or equal to the preset temperature threshold.

In one possible implementation, the method further includes:

When the rotating speed of the first motor is greater than or equal to a high-flow-speed rotating speed threshold value, controlling the second motor to operate in a high-loss mode;

The loss heating power of the operation working condition of the second motor when the second motor operates in the high-loss mode is larger than a high-speed state heat dissipation power threshold; the high-speed state heat dissipation power threshold is determined according to a high-speed state rotating speed threshold, wherein the high-speed state rotating speed threshold is the rotating speed which can be reached by the first motor when the oil temperature reaches the high-speed state temperature threshold.

In one possible implementation manner, the second motor is a driving motor for driving wheels to rotate in an electric automobile; the electric automobile further includes: a heat collecting device; the heat collecting device is a battery or cabin heating device; the heat collecting device is in heat exchange connection with the oil pipeline through a heat exchanger; the heat exchanger is positioned on the oil pipeline from the second motor to the first motor;

Before the obtaining the start control instruction of the second motor, the method further includes:

And acquiring a starting instruction of the heat collecting device.

In a second aspect, an embodiment of the present application provides a heating control method, including:

Injecting heating current into a first motor operating based on energy-saving current when the rotating speed of the first motor is smaller than the target rotating speed in a target operating condition;

The first motor is an oil pump motor in the oil pump, and the heating power of the heating current is larger than that of the energy-saving current; the energy-saving current is a current which can enable the first motor to reach the target operation working condition when the oil temperature is greater than a preset temperature threshold value.

In one possible implementation, the method further includes:

and injecting the energy-saving current into the first motor when the rotating speed of the first motor working based on the heating current is greater than or equal to the target rotating speed.

In a third aspect, an embodiment of the present application provides a heating control method, including:

Injecting heating current into the first motor when the first motor meets the low-loss working condition;

Wherein the first motor is an oil pump motor in an oil pump; the low-loss working conditions include: the loss heating power corresponding to the operation working condition of the first motor is smaller than an expected loss heating power threshold, or the operation working condition of the first motor is a low-loss working condition, wherein the loss heating power of the low-loss working condition is smaller than the expected loss heating power threshold; the heating power of the heating current is larger than that of the energy-saving current, wherein the energy-saving current is a current which can enable the first motor to reach the target operation working condition when the oil temperature is larger than a preset temperature threshold.

In still another aspect, an embodiment of the present application provides an oil pump, including: a first motor and a control device for performing the method of any one of the first to third aspects.

In yet another aspect, an embodiment of the present application provides a heat exchange system, including: the device comprises a first motor, a control device, a second motor, an oil pipeline, a heat exchanger and a heat collecting device;

Wherein the second motor is an oil-cooled motor; the first motor is an oil pump motor in an oil pump, and the oil pump is used for providing cooling oil for the second motor through the oil delivery pipeline;

The heat exchanger is positioned on an oil pipeline from the second motor to the first motor; the heat collecting device is in heat exchange connection with the oil pipeline through the heat exchanger;

the control means is adapted to perform to implement the method of any one of the first to third aspects.

In one possible implementation manner, the heat collecting device is: a battery; or cabin heating device

In still another aspect, an embodiment of the present application provides a control apparatus, including: a memory and a processor;

Wherein the memory is for storing instructions and the processor is for executing instructions to implement the method of any one of the first to third aspects.

In yet another aspect, an embodiment of the present application provides a control device, where the device includes a processing module and a transceiver module, and the processing unit executes instructions to control the device to perform a method in any one of the possible designs of the first aspect to the third aspect.

In one possible implementation, the apparatus may further include a storage module.

In one possible implementation, the device may be a controller or a chip within a controller.

When the device is a controller, the processing module may be a processor and the transceiver module may be a transceiver; if a memory module is also included, the memory module may be a memory.

When the device is a chip in the controller, the processing module may be a processor, and the transceiver module may be an input/output interface, a pin, or a circuit, etc.; if a memory module is included, the memory module may be a memory module (e.g., a register, a cache, etc.) within the chip, or may be a memory module external to the chip (e.g., a read-only memory, a random access memory, etc.).

The processor mentioned in any of the above may be a general purpose central processing unit (Central Processing Unit, CPU for short), a microprocessor, an application-specific integrated circuit (ASIC for short), or one or more integrated circuits for controlling the execution of the program of the spatial multiplexing method of the above aspects.

In one example, the controller may be a control center of an electric vehicle.

In yet another aspect, the present application provides a computer-readable storage medium having instructions stored therein that are executable by one or more processors on a processing circuit. Which when run on a computer causes the computer to perform the method in any of the possible implementations of the first to third aspects described above.

In a further aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of any of the possible implementations of the first to third aspects.

Drawings

In order to more clearly illustrate the application or the technical solutions of the prior art, the following description of the embodiments or the drawings used in the description of the prior art will be given in brief, it being obvious that the drawings in the description below are some embodiments of the application and that other drawings can be obtained from them without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a first motor according to an embodiment of the present application;

fig. 2 is a schematic diagram of a second structure of the first motor according to the embodiment of the application;

FIG. 3 is a schematic diagram of an oil pump including a first motor according to an embodiment of the present application;

Fig. 4A is a schematic structural diagram of an oil pump to which the heating control method according to the embodiment of the present application is applied;

FIG. 4B is a schematic diagram of a heat exchange system to which the heating control method according to the embodiment of the present application is applied;

FIG. 4C is a schematic diagram of a heat exchange system to which the heating control method according to the embodiment of the present application is applied;

FIG. 5A is a schematic diagram of a three-phase full-bridge circuit according to an embodiment of the present application;

FIG. 5B is a schematic representation of the d-axis current vector in an embodiment of the present application;

FIG. 5C is a schematic diagram of integrated vector currents in a dq axis rotation coordinate system in an embodiment of the present application;

FIG. 5D is a schematic diagram of integrated vector currents in a three-phase rotating coordinate system according to an embodiment of the present application;

FIG. 6 is a flow chart of a heating control method according to an embodiment of the application;

FIG. 7 is a second flow chart of a heating control method according to an embodiment of the application;

FIG. 8 is a schematic diagram of the heating mode current applied to the SPM motor according to the embodiment of the present application;

FIG. 9 is a schematic diagram of a heating mode current determined based on the Min-TPA mode in an embodiment of the application;

Fig. 10 is a schematic diagram of a mapping relationship between an external characteristic curve corresponding to an operation condition of a first motor and a corresponding loss heating power in an embodiment of the present application;

FIG. 11 is a third schematic flow chart of a heating control method according to an embodiment of the present application;

FIG. 12 is a schematic diagram of a control device according to an embodiment of the present application;

fig. 13 is a schematic diagram of a control device according to an embodiment of the application.

Detailed Description

The terminology used in the description of the embodiments of the application herein is for the purpose of describing particular embodiments of the application only and is not intended to be limiting of the application.

Example 1

The embodiment of the application provides a group of heating control method and device, and a first motor and a heat exchange system applying the heating control method. Wherein the vicinity of the first motor may be provided with a passage for allowing the passage of liquid.

For example, the first motor may be an oil pump motor, an oil cooling motor, etc., and the liquid used in cooperation with the first motor may be oil.

As an example, the oil pump motor may be an electric pump or a motor in an oil pump for driving a flow of liquid. The oil pump can be provided with an oil pumping cavity for accommodating oil to be driven, and the oil pump motor can drive the oil in the oil pumping cavity through transmission connecting pieces such as fan blades.

As an example, an oil-cooled motor may be a motor that uses cooling oil to cool the motor. The oil-cooled motor may be internally provided with a passage allowing the oil to pass through, or the oil-cooled motor may be located in a cooling chamber containing cooling oil. The oil flowing in the internal passage of the oil-cooled motor or the oil flowing in the cooling cavity outside the oil-cooled motor can be used for carrying heat generated in the running process of the oil-cooled motor.

It should be noted that, the oil pump motor can adopt the oil cooling mode to cool down and also can adopt other cooling modes to cool down, when the oil pump motor adopts the oil cooling mode to cool down, the oil pump motor inside also can set up the passageway that allows oil to pass through or the oil pump motor also can set up and be located the cooling intracavity, adopts the oil pump motor of this kind of setting mode also to be an oil cooling motor. In embodiments of the present application, allowing oil to pass through a space may be referred to as over-oiling, and the passage or space area allowing oil to pass through may be referred to as over-oiling passage or over-oiling area.

As an example, the oil used in conjunction with the first electric machine may be cooling oil, lubricating oil, insulating oil, high voltage resistant oil, or the like.

In some low temperature scenarios, the first motor may not work properly due to the high viscosity of the oil. For example, for an oil pump motor, when the oil temperature in the oil pump cavity is low, the torque output after the oil pump motor is started cannot push the oil to move, and the oil pump motor cannot even rotate. For an oil-cooled motor, when the oil temperature in the vicinity of the inside or outside of the oil-cooled motor is low, the flow capacity of the oil is reduced to an extremely low level, so that heat generated by the oil-cooled motor cannot be taken away in time, and the risk of burning of the motor exists.

The heating control method in the embodiment of the application can utilize the first motor to heat the oil in the adjacent area of the first motor so as to solve the problems.

In an embodiment of the present application, the adjacent area of the first motor may include an oil passing area inside the first motor and an oil passing area outside the first motor. In other embodiments of the present application, the structure and location of the first motor will be described in detail.

The structure of the first motor in the embodiment of the present application is exemplarily described below.

Fig. 1 is a schematic structural diagram of a first motor according to an embodiment of the application.

As shown in fig. 1, the first motor may include: stator, rotor, motor housing. Wherein, the motor housing encloses a motor cavity, and the motor cavity can be used for holding stator and rotor. As an example, the stator may include a stator core, stator windings, and the rotor may rotate about a rotor shaft disposed within the machine cavity. As an example, the number of rotors may be 3. The embodiments of the present application are not limited in this regard.

In an embodiment of the present application, referring to fig. 1, one or more oil passing areas allowing oil to pass may be provided inside the first motor.

As an alternative embodiment, an oil passage for passing oil may be provided in the rotor shaft. Wherein the oil passage may be adapted to communicate with an oil delivery line located outside the first motor. It should be noted that the oil duct and the oil delivery pipeline may not pass through the cavity in the motor cavity.

As an alternative embodiment, an oil hole for passing oil may be provided in the rotor. Wherein, this oilhole can be used for communicating with oil pipeline. It should be noted that, the oil hole and the oil pipeline are communicated without passing through the cavity in the motor cavity.

As an alternative embodiment, the motor housing may be adapted to communicate with the oil delivery line. As an example, the cavity portion that can be seen in fig. 1 can be an area in the motor cavity where oil can pass. It should be noted that, when the motor cavity is communicated with the oil delivery pipeline, the oil duct and the oil hole can also be communicated with the oil delivery pipeline through the motor cavity.

By adopting the arrangement mode, when the oil conveying pipeline passes through oil, the oil can be passed through the motor cavity, the rotor positioned in the motor cavity can be immersed in the oil, so that the rotor and the oil can be in direct contact and the heat transfer surface between the rotor and the oil is larger, and the efficiency of heating the oil by the first motor can be improved when the oil is heated by utilizing the heat of the first motor.

As an alternative embodiment, the gap between the rotor and stator windings may be referred to as an air gap, and the air gap between the rotor and stator windings may be used to communicate with the oil line. As an example, the air gap may be in communication with the motor cavity and with the oil delivery line through the motor cavity.

By adopting the arrangement mode, when oil exists in the motor cavity, the air gap can be used for passing the oil, so that the heat transfer surface between the heating rotor and the oil is larger and more direct, and the efficiency of heating the oil by the first motor can be improved.

In this embodiment of the present application, as an optional implementation manner, when the first motor is an oil pump motor, a mode of communicating the motor cavity with the oil delivery pipeline and communicating the air gap with the oil delivery pipeline may be adopted. When the first motor is a non-oil pump motor which is mainly used for outputting mechanical energy, for example, when the driving motor in an electric automobile adopts an oil cooling mode for cooling, a motor cavity and an air gap can be arranged and are not communicated with an oil pipeline. By adopting the arrangement mode, the proportion of electric energy converted from injected current into heat energy when the oil-cooled motor is in a rotating state can be controlled.

Fig. 2 is a schematic diagram of a second motor according to an embodiment of the application.

Unlike the structure shown in fig. 1, the cavity and the air gap between the stator and the rotor in fig. 2 may not be in communication with the oil delivery line, as an example. In this arrangement, the air gap is not oil-filled. The mode that the air gap is arranged in the driving motor and is the area which is not allowed to pass through oil is adopted, so that the proportion of converting electric energy into heat energy can be reduced, heating loss is further reduced, and electric energy is converted into mechanical potential energy more.

In the embodiment of the present application, the oil passing area outside the first motor may be set in the following manner. The first motor is described below as an example of an oil pump motor in the oil pump.

Fig. 3 is a schematic structural diagram of an oil pump including a first motor according to an embodiment of the present application.

As shown in fig. 3, as an example, the oil pump may include: pump chamber, fan blades (not shown), etc. The oil pump motor can be positioned in an oil pump cavity of the oil pump, and a liquid inlet and a liquid outlet of the oil pump cavity can be respectively communicated with the oil conveying pipeline. At this time, the motor casing outer side of the first motor may be in contact with the oil in the pump oil chamber. The first motor may be used to heat oil located within the first motor and oil located outside the first motor and within the pumping chamber. I.e. the oil in the vicinity of the oil pump motor may comprise oil located in the oil pump chamber. In other embodiments of the present application, the oil-cooled motor may also be disposed within a temperature-reducing chamber that is permeable to oil, i.e., the oil in the vicinity of the oil-cooled motor may include oil within the temperature-reducing chamber.

It should be noted that, the first motor to which the heating control method provided by the embodiment of the present application is applied may have at least one of the above-mentioned various inner oil passing areas or the above-mentioned various outer oil passing areas.

In the embodiment of the present application, the execution subject of the heating control method may be a control device. The control device can be arranged in various ways.

In an example, the control device may be provided on the first motor. For example, when the first motor is an oil pump motor or a drive motor, the control means may be a control unit in the oil pump motor or the drive motor, which control unit may be implemented in software or hardware.

In yet another example, the control device may be provided on the oil pump when the first motor is an oil pump motor in the oil pump.

Fig. 4A is a schematic structural diagram of an oil pump to which the heating control method according to the embodiment of the present application is applied. As an example, as shown in fig. 4A, the oil pump 81 may include: an oil pump motor 82 and a control device 90.

In yet another example, the first motor may be an oil pump motor in an oil pump, and the oil pump is an oil pump for driving oil in a heat transfer oil passage in a heat exchange system in which the control device may be located.

Referring to fig. 4B, a schematic diagram of a heat exchange system to which the heating control method according to the embodiment of the present application is applied is shown. As shown in fig. 4B, as an example, the heat exchange system 900 may include: a control device 90, a heating device 83, an oil pump 81 including an oil pump motor 82, a heat collecting device 84, and an oil delivery pipeline. Wherein the oil delivery line is not shown in fig. 4B. In one example, the oil delivery pipeline can be used for sequentially connecting the oil pump, the heating device and the heat collecting device into a circulation loop.

In practical applications, the heat exchange system may be an electric vehicle or located on an electric vehicle, for example.

As an example, the heating device may be a driving motor for driving the tire to rotate in the electric vehicle, or other electric appliances capable of heating in the electric vehicle.

As an example, the heat collecting device may include a battery in an electric vehicle, a cabin heating device, or the like, which needs to collect and utilize heat energy. For example, the battery may be used for a driving motor, an electric appliance, or the like that rotates a driving tire in an electric automobile. The battery may also be referred to as a battery pack. In one example, the cabin heating device may be an on-board air conditioner or the like. In practical applications, a temperature sensor may also be provided in the battery pack or in the cabin heating device.

Taking a heat generating device of the heat exchange system as a driving motor, a heat collecting device in the heat exchange system includes a battery as an example, and fig. 4C is a schematic structural diagram of a heat exchange system to which the heating control method provided by the embodiment of the present application is applied.

As shown in fig. 4C, the heat exchange system may include devices disposed on two cyclical thermal conductive loops. Wherein, the device that is located on the oil circuit includes: the driving motor, the heat exchanger and the oil pump are sequentially connected through the oil pipeline; the device on the waterway (only part of the waterway is shown in the figure) comprises a micro control unit MCU, a heat exchanger and a battery which are sequentially connected through a water pipe. The heat exchanger is used for transferring heat of oil in the oil way to water in the water way.

It should be noted that the control device may be located on the oil pump motor, or the control device may be located on the drive motor, or the control device may be located in a control center of the electric vehicle. The control device can be electrically connected with the oil pump motor and the driving motor. The position of the control device is not shown in fig. 4C.

In an alternative embodiment of the heat exchange system, as an example, the heat collection device may include a heat exchanger, a heat exchange circuit, and a battery. Wherein, the battery is located the heat transfer circuit, and the heat exchanger is still located the heat transfer circuit. In one example, the heat exchanger may be an oil-water heat exchanger, which may be a passive device. In an example, the heat exchange circuit may be a water pipe corresponding to the waterway in fig. 4C.

In an alternative embodiment of the heat exchange system, as an example, one or more temperature sensors may also be included in the heat exchange system.

As an example, a temperature sensor may be located in the vicinity of the first motor for obtaining the temperature of the oil in the vicinity of the oil pump motor. In one example, the temperature sensor may be located in the vicinity of the drive motor or in the oil line for obtaining the temperature of the oil in the vicinity of the drive motor or in the oil line. The control device can use various temperature data obtained by the sensor to control correspondingly. In other embodiments of the present application, control steps in a control scenario of a heat exchange system will be described in detail.

In the embodiment of the application, the first motor applying the heating control method may also be a motor with a built-in permanent magnet.

As an example, the rotor in the first motor may be made using permanent magnets. In one example, the first motor may be a Surface-Mounted permanent magnet motor (Surface-Mounted PERMANENT MAGNET MACHINE, SPM), where the SPM motor is a permanent magnet motor with permanent magnets fixed to the rotor Surface. In yet another example, the first electric machine may be an Interior permanent magnet machine (Intoror PERMANENT MAGNET MACHINE, IPM), wherein the IPM machine may be a permanent magnet machine with permanent magnets embedded inside the rotor.

The first motor with the built-in permanent magnet can excite more loss heating when heating current is injected, and the heating current injected by the motor with the built-in permanent magnet and the heating current injected by the SPM motor and the IPM motor are described in detail in other embodiments of the application.

In an embodiment of the present application, the first motor may include a three-phase circuit for injecting three-phase currents into the three rotors.

Taking the example that the first motor has three rotors, various heating currents injected into the first motor by the heating control method in the embodiment of the application can be three-phase currents injected into the first motor by utilizing a three-phase circuit. For example, the three-phase circuit may be a three-phase full-bridge circuit, a three-phase half-bridge circuit, a three-phase series-parallel circuit, etc., and referring to fig. 5A, one example of the three-phase full-bridge circuit is shown, and fig. 5B is one example of the d-axis current vector. The embodiments of the present application are not limited in this regard.

It should be noted that the three-phase current may also be referred to as three-phase power. The three-phase power can be a group of three-phase alternating currents with equal amplitude, equal frequency and 120-degree phase difference. In a stationary three-phase coordinate system, the three-phase currents may be represented as i _a、i_b and i _c (or i _u、i_v and i _w). The control targets of various currents related to the heating control method in the embodiment of the application can be replaced by the equivalent control targets of the integrated vector current. In the motor analysis process, three-phase current in a static three-phase coordinate system can be converted into comprehensive vector current in a rotating coordinate system by utilizing park conversion (Park Transformation), so that motor analysis is simplified.

For example, the rotating coordinate system may be a dq rotating coordinate system, where the d-axis is the same as the a-axis where i _a is located (or the u-axis where i _u is located) in the three-phase coordinate system. Fig. 5C Is a schematic diagram of integrated vector currents under the dq rotation coordinate system according to an embodiment of the present application, and as shown in fig. 5C, the integrated vector currents Is corresponding to the three-phase currents in the dq rotation coordinate system may be represented as a combined vector determined by a direct axis (direct axis) current Id and an quadrature axis (q-axis) current Iq. The integrated vector current Is may also be represented by an amplitude and a position angle θ, where the position angle θ Is an angle between the integrated vector current Is and the d-axis. The integrated vector current Is may also be represented by the quadrature axis current Iq and the current lead angle γ. The current lead angle gamma Is the included angle between the integrated current vector Is and the quadrature axis q-axis.

As another example, the rotating coordinate system may also be a three-phase rotating coordinate system, and fig. 5D is a schematic diagram of integrated vector current under the three-phase rotating coordinate system in an embodiment of the present application.

In practical application, the integrated current vector is also used as an integrated vector current, and the adjustment of the integrated vector current can be realized by adjusting the magnitude of the direct axis current, the magnitude of the quadrature axis current, the magnitude of the position angle θ, and the like, and various heating currents injected into the first motor by the heating control method will be described in detail in the following embodiments.

The heating control method provided by the embodiment of the application is exemplified below.

Based on any one of the first motors provided in the foregoing embodiments, an embodiment of the present application provides a set of heating control methods. The control device can heat the oil in the vicinity of the first motor by injecting heating current into the first motor and exciting the first motor to self-heat.

In practical application, the temperature of the first motor before starting is close to the temperature of the operating environment of the first motor, after the first motor is started, in order to achieve the target operating condition, the first motor is injected with working current, and in the operation process of the first motor, the first motor generates heat, part of electric energy is converted into heat energy, so that the temperatures of the first motor and the adjacent areas are gradually increased.

In the embodiment of the application, the control device can firstly determine whether the first motor reaches a cold state condition, and when the first motor is determined to be heated, heating current is injected into the first motor, wherein the cold state condition can be set based on decision information such as the temperature of the adjacent area of the first motor, the oil temperature of the adjacent area of the first motor, the rotating speed of the first motor and the like.

Note that, when the first motor is an oil pump motor, the flow rate of oil is related to the rotation speed of the first motor, and table 1 is a set of schematic diagrams of the oil temperature and the flow rate of oil.

TABLE 1

The oil temperature, the oil flow rate and the rotation speed of the first motor have linear relation, when the oil temperature reaches a high-speed state temperature threshold, the oil flow rate can reach the high-speed state flow rate threshold, when the oil temperature is low to a cold temperature threshold, the oil flow rate is reduced to a locked-rotation state flow rate threshold, the first motor can reduce the reached rotation speed to the locked-rotation state flow rate threshold, the locked-rotation state flow rate threshold can be 0 or a smaller value, and the locked-rotation state flow rate threshold can be 0 or a smaller value. When the oil temperature rises from the cold state temperature threshold to the high speed state temperature threshold, the flow rate of the oil can rise from the locked state flow rate threshold to the high speed state flow rate threshold, and the rotation speed of the first motor can gradually rise from the locked state rotation speed threshold to the high speed state rotation speed threshold. As an example, the cold temperature threshold may be a temperature at which the viscosity of the oil reaches a preset viscosity threshold, and when the viscosity of the oil reaches the preset viscosity threshold, a moving speed of the oil located in a vicinity of the first motor under the pushing of the start torque of the first motor is less than or equal to a preset low-speed state flow rate threshold. In an example, the preset low-speed flow rate threshold may be 0, and when the oil temperature is lower than the cold temperature threshold, the viscosity of the oil may reach a very high level, and the torque generated when the first motor is started may not even push the oil because the viscosity is too high.

Based on the table 1, the control device may determine that the cold condition is satisfied when the oil temperature does not reach the high-speed state temperature threshold, or the flow rate of the oil does not reach the high-speed state flow rate threshold, or the rotation speed of the first motor does not reach the high-speed state rotation speed threshold. It should be noted that, by using the rotational speed of the first motor to determine whether the temperature of the operating environment of the first motor is lower than the high-speed temperature threshold, it may not be necessary to provide a temperature sensor in a vicinity of the first motor, such as the oil delivery line and the oil pumping chamber.

In the embodiment of the application, the control device may further set different cold conditions before or after the first motor is started, and set a corresponding heating current implementation mode for different cold conditions.

Table 2 is a set of schematic representations of different cold conditions and corresponding heating and energy saving currents.

TABLE 2

As shown in table 2, the cold condition may be a cold warm-up condition when the first motor is in an inactive state, and the cold condition may be a locked-rotor heat-up condition or a low-speed heat-up condition when the first motor is in an active state.

As shown in table 2, when the heating condition is not satisfied, the control device may set not to inject the heating current into the first motor, and may inject the energy-saving current into the first motor according to the target operation condition of the first motor, where the energy-saving current may be a current that can make the first motor reach the minimum amplitude or the highest energy efficiency of the target torque and the target rotation speed, so as to avoid unnecessary heating loss. The various cold conditions and alternative embodiments of the heating current shown in table 2 will be described in detail in the examples below in connection with the process flow in actual practice.

Alternative implementations of the process flow of the heating control method provided in the embodiment of the present application are described below. It should be noted that, various alternative implementations in the embodiments of the present application may be used alone or in combination.

Fig. 6 is a schematic diagram illustrating a heating control method according to an embodiment of the present application. As shown in fig. 6, the steps of the embodiment of the present application may include:

S101, when the first motor is in an un-started state, a starting instruction of the first motor is obtained.

S102, determining whether the first motor meets the cold state preheating condition, if so, executing S103, and if not, executing S104.

As an example, the control device may set the first motor to enter the preheating mode when it is determined that the cold preheating condition is satisfied, and may directly start the first motor when the cold preheating condition is not satisfied.

In the examples of the present application, there are various embodiments of the cold pre-heating conditions. Table 1 is an illustration of one set of embodiments of cold preheat conditions.

TABLE 3 Table 3

As shown in table 3, as an alternative embodiment, the control device may determine whether the cold warm-up condition is reached by temperature data acquired by temperature sensors provided in other devices in the vicinity of the first motor when the first motor is in the non-activated state.

In other embodiments of the present application, as an example, the control means may not inject the preheating current into the first motor when the first motor is in a stationary state and the temperature of the vicinity of the first motor is higher than the cold temperature threshold.

S103, injecting a preheating current into the first motor.

In embodiments of the present application, the preheat current may take the form of a combination of one or more of the following implementations. The following description will take, as an example, a comprehensive vector current corresponding to the preheating current I ₁ as the first vector current Is ₁, a direct axis current of the first vector current Is I _d1, and a quadrature axis current Is I _q1,I_MAX, which Is a maximum current amplitude supported by the first motor.

In one embodiment of the preheating current, when the first motor is a motor with built-in permanent magnets, a direction angle of a first vector current corresponding to the preheating current is a variable, and/or an amplitude of the first vector current is a variable; the direction angle of the first vector current is an included angle between the first vector current and a d axis in the dq rotating coordinate system.

In practical application, the control device can be realized by setting a through-flow mode of the comprehensive vector current corresponding to the preheating current. Table 4 is a set of schematic diagrams of the preheat current and loss type for the first motor. The first vector current may be any of the integrated current vector current methods shown in table 4.

TABLE 4 Table 4

The current methods in table 4 include dc, ac with dc bias. Wherein direct current means that the magnitude of the preheat current does not change over time. Ac means that the magnitude of the preheat current varies with time. Alternating current with a dc bias indicates that the amplitude varies with time and the average value of the current over a period is not zero and can be either positive or negative (either on the positive half-axis only or on the negative half-axis only). The angle may refer to the phase of the integrated vector current.

Any combination of the through-flow mode and the direction angle can excite the first motor to generate heating loss.

The types of losses excited in table 4 include copper loss, iron loss, and permanent magnet loss. Copper loss may refer to heat generated by alternating current/direct current passing through a copper conductor, and heating power is calculated by using I ² R, wherein I is passing current (direct current or effective value of alternating current quantity), and R is conductor resistance. The iron loss may refer to the loss of ferromagnetic materials (e.g., steel, silicon steel sheet, etc.) in an alternating magnetic field, and may include hysteresis loss, eddy current loss, parasitic loss, etc. The permanent magnet loss is generated because the permanent magnet material has conductivity, eddy current is induced in the alternating magnetic field, and corresponding eddy current loss is generated, and the permanent magnet loss can be calculated by using I ² R, wherein I is the eddy current induced and R is the eddy current loop resistance.

The magnetic field types in table 4 include constant magnetic field, rotating magnetic field, and pulsating magnetic field. The pulse vibration magnetic field can refer to a magnetic field with a constant direction and only a periodically-changed amplitude along with time. The rotating magnetic field may refer to a magnetic field whose magnitude is variable and whose direction varies periodically with time in space over the circumference. A constant magnetic field may refer to a magnetic field that does not vary in magnitude or direction over time.

The integrated vector currents corresponding to the through-flow patterns and the direction angle combinations of the numbers 1,4, and 7 in table 4 do not generate torque, and the integrated vector currents corresponding to the through-flow patterns and the direction angle combinations of the other numbers in table 4 generate torque.

It should be noted that, when the first motor is in the non-started state, the integrated vector currents indicated by the numbers 1, 4, and 7 in table 4 may be used as the preheating current, so that it is possible to avoid converting part of the electric energy into mechanical energy due to the torque.

It should be noted that, the combination vector currents corresponding to the through-flow modes and the direction angle combinations with the serial numbers of 4 and 7 not only can excite copper loss and iron loss, but also can excite permanent magnet loss, and the two combination vector currents are adopted as the implementation mode of preheating current, so that the loss heating power of the first motor is larger, and the oil in the adjacent area of the first motor can be heated more rapidly.

In the embodiment of the application, the first motor can adopt a motor with built-in permanent magnets, such as an SPM motor and an IPM motor, so that more loss is excited in a preheating mode, and oil in the adjacent area of the first motor can be heated more quickly.

In another embodiment of the preheat current, the preheat current may be a zero torque current that is capable of zero torque produced by the first motor. When zero torque current is injected into the first motor, the first motor does not rotate, and at the moment, the electric energy of the first motor is not converted into mechanical energy, so that the proportion of the electric energy corresponding to the preheating current to the heat energy is higher.

In practice, table 5 is a set of schematic representations of the corresponding preheat currents for an SPM motor and an IPM motor.

TABLE 5

It should be noted that, the through-current mode of the direct-axis current I _d1 may be a direct current, an alternating current or an alternating current mode with a direct current bias, where the direct current represents a waveform whose amplitude and phase do not change with time; alternating current represents a waveform with unchanged phase, alternately changed amplitude with time and positive and negative, and zero average value; alternating current with a direct current bias represents a waveform whose phase is unchanged, amplitude varies with time positive and negative (either in the positive half-axis only or in the negative half-axis only), and the average value is not zero.

S104, starting the first motor.

It should be noted that S102 is not a step that must be performed in the embodiment of the present application.

By adopting the mode of injecting the preheating current into the first motor when the first motor is in the static state and the temperature of the adjacent area is lower than the cold state temperature threshold value, the first motor can be driven to generate self-heat when the first motor is in the static state, and the oil in the adjacent area of the first motor is heated by utilizing the heat generated by the first motor, so that the temperature of the oil in the adjacent area rises to be higher than the cold state temperature threshold value as soon as possible, the viscosity of the oil is reduced to the extent that the first motor can push or is easier to push, and the problem that the motor is extremely difficult to start and rotate due to poor fluidity of the oil when the oil temperature is lower than the cold state temperature threshold value can be avoided, and the first motor can push the oil more easily when the first motor starts to rotate.

In a second alternative embodiment of the heating control method, the heating current may be a heating current.

Fig. 7 is a second flowchart of a heating control method according to an embodiment of the application.

As shown in fig. 7, when the first motor is in a start state, the steps of the embodiment of the present application may include:

s111, when the first motor is in the locked state, determining whether the first motor meets the locked state heating condition, if so, executing S112, and if not, executing S113.

Wherein, table 6 is a schematic representation of the locked-rotor heating conditions.

TABLE 6

S112, injecting a first heating current into the first motor.

As an example, the control target of the first heating current may be the same as the preheating current in the foregoing embodiment when the rotation speed of the first motor is 0. As an example, when the rotation speed of the first motor is not 0, the control target of the first heat increasing current may be the same as that in the foregoing embodiment.

It should be noted that S111 and S112 are not steps that must be performed in the embodiment of the present application.

S113, when the first motor is in a low-speed state, determining whether the first motor meets a low-speed state heating condition, if so, executing S114, and if not, executing S115.

Wherein, table 7 is a schematic representation of low-speed state heat increasing conditions.

TABLE 7

In the embodiment of the present application, as an alternative implementation manner, based on the heating condition shown in the judgment condition example 2, the control device may selectively set the first motor to the heat increasing mode or the energy saving mode based on whether the first motor satisfies the heating condition.

For example, the first motor is set to the heat increasing mode when it is determined that the first motor needs to increase heat generation to meet the heating condition. When it is determined that the first motor does not satisfy the heating condition, the first motor is set to the energy saving mode. The control device may control the first motor to operate based on the heating current when the first motor is in the heating mode. When the first motor is in the energy saving mode, the control device can control the first motor to work based on the energy saving current.

S114, injecting a second heating current into the first motor.

As an example, the control target of the second heating current may be the same as that in the foregoing embodiment.

In the embodiment of the application, the amplitude of the comprehensive vector current corresponding to the heat increasing current is larger than that of the comprehensive vector current corresponding to the energy saving current.

In the embodiment of the application, the energy-saving current can be an integrated vector current for enabling the first motor to reach a target operation working condition and meeting a condition with smaller amplitude, or the energy-saving current can be an integrated vector current for enabling the first motor to reach the target operation working condition and meeting a condition of overall efficiency.

In one example, the lesser magnitude condition may be a combined vector current that minimizes the magnitude of the first motor reaching the target operating condition. In one example, the overall efficiency condition may be a combined vector current that causes the first motor to reach a target operating condition with the highest overall efficiency. As one example, the overall efficiency may be determined from the duty cycle of the lost heating power in the total power. As an example, the integrated vector current that can be determined according to the maximum efficiency unit current control scheme (Max EFFICIENCY PER AMPERE, MEPA) can be considered to satisfy the integrated vector current that is most efficient in the overall machine.

In this embodiment of the present application, as an optional implementation manner, the control device may first determine an energy-saving current corresponding to a current target operating condition of the first motor, and then obtain the heating current by adjusting a current lead angle of a comprehensive vector current corresponding to the energy-saving current.

In practical application, fig. 8 is a schematic diagram of a heating current applied to an SPM motor in an embodiment of the application. Fig. 9 is a schematic diagram of a heating current determined based on Min-TPA mode in an embodiment of the present application. Table 8 is a set of schematic representations of the corresponding power saving and heating currents for SPM and IPM machines.

TABLE 8

It should be noted that, for the IPM oil pump motor, max-TPA control (Maximum Torque per unit current control, maximum Torque PER AMPERE) may be adopted in operation, and in the embodiment of the present application, by adjusting the current lead angle (i.e., the angle between the current integrated vector and the q-axis), min-TPA control (Minimum Torque per unit current PER AMPERE) is adopted, so that heat generation of the oil pump motor may be increased in operation, and the heating effect on surrounding oil may be further improved.

Referring to FIG. 9, both Tem1 and Tem2 are equal torque curves, where T _em1＞T_em2. A circle taking the O point as the center of a circle is taken as an intersecting-straight axis current relation circle, wherein the relation circle adoptsAnd (5) determining. Three ellipses taking coordinates (- ψ _f, 0) as center points are rotation speed voltage relation ellipses expressed by current, wherein the relation ellipses are determined by (L _qI_q)²+(L_dI_d+ψ_f)²≤(u_lim/ω²), wherein L _d is inductance, u _lim is a direct current bus voltage limit value, ω is rotation speed, ψ _f is permanent magnet flux linkage generated by a permanent magnet, and rotation speeds corresponding to the three ellipses meet ω ₁＜ω₂＜ω₃.

As an example, the operating point determined by the minimum magnitude integrated vector current capable of achieving the torques Tem1 to Tem2 may constitute a curve from point a, which is the operating point capable of achieving the minimum magnitude integrated vector current of the torque Tem1, to point B, which is the operating point capable of achieving the minimum magnitude integrated vector current of the torque Tem 2. The current that can reach the maximum amplitude of the torque Tem2 may be C.

In the normal working mode, when the required torque is Tem2, the working point determined by the Max-TPA control mode is at the point a in fig. 8, that is, the point a is the coordinate point of the integrated vector current corresponding to the energy-saving current, and the working point determined by the Min-TPA control mode is at the point C in fig. 8, that is, the point a is the coordinate point of the integrated vector current corresponding to the heating current, which can be shown in fig. 8, and the point C and the point a are located on the equal torque curve Tem1, that is, the two working points can satisfy the same torque output, but the working current amplitude is different, the current amplitude of the point C can reach the supported maximum value, and the current amplitude of the point C is greater than the point a, so that the heating of the motor can be further improved under the premise of satisfying the same torque output by the operating condition of the point C. As an alternative embodiment, the heating current may also be on a curve from point a to point C.

In the embodiment of the application, a group of current amplitude values and current lead angles corresponding to loads and torques can be tested in advance, and then the current lead angles can be adjusted directly according to the current amplitude values. The current lead angle was adjusted so that the torque of the resulting heating mode current became larger relative to the energy saving mode current determined using Max-TPA. This determination may also be referred to as Min-TPA control.

As an alternative embodiment, any one of the through-flow modes and the included angle combination embodiments of the integrated current vectors corresponding to the numbers 2,3, 5,6, 8, and 9 of the torque generated in table 4 may be used as the heating current.

It should be noted that S113 and S114 are not steps that must be performed in the embodiment of the present application.

S115, injecting energy-saving current into the first motor.

In the embodiment of the present application, the implementation of the energy saving current may be referred to the related description in S114.

By adopting the heating current provided by the embodiment of the application, when the first motor is in the starting state, the first motor can reach the target operation condition, and meanwhile, the oil in the adjacent area of the first motor can be continuously heated.

In the embodiment of the application, the control device may also determine whether to inject the heating current when the rotation speed of the first motor is in one or more of a stationary state, a locked-rotor state, and a low-speed state, and inject the heating current corresponding to each state when it is determined that the heating current needs to be injected.

Table 9 is a set of schematic illustrations of the correspondence relationship between the heating currents injected into the first motor in each state in the embodiment of the present application.

TABLE 9

In the embodiment of the present application, various judging conditions such as heating conditions and cold conditions may be used as judging conditions for whether the oil in the vicinity of the first motor needs to be heated, and the judging conditions may be used in combination at different stages.

In the embodiment of the present application, as an example, for the oil pump motor being an SPM motor, the oil pump motor and the driving motor in a cold state heat the oil in a mode of "id=alternating current, iq=0" or "Id direct current, iq=0" at first; after the surrounding oil temperature rises, the full power operation is directly given for the working condition that the load torque reaches the maximum torque, iq=Iq_max, and the current lead angle is adjusted for the working condition that the load torque does not reach the maximum torque, so that the output torque meets the load requirement, and meanwhile, the loss is maintained. Wherein, id=alternating current means that the through-flow mode of the direct current is an alternating current mode, that is, the amplitude of the direct current changes with time, and id=direct current means that the through-flow mode of the direct current is a direct current mode, that is, the amplitude of the direct current does not change with time.

In the embodiment of the present application, as an example, for an oil pump of the interior permanent magnet motor (IPM) type, the oil pump motor and the driving motor in a cold state firstly adopt a mode of "id=alternating current, iq=0" or "Id direct current, iq=0" to heat the oil at the same time; after the surrounding oil temperature is increased, the traditional Max-TPA control is changed into Min-TPA control, and the oil is further heated; wherein, id=alternating current means that the through-flow mode of the direct current is an alternating current mode, that is, the amplitude of the direct current changes with time, and id=direct current means that the through-flow mode of the direct current is a direct current mode, that is, the amplitude of the direct current does not change with time.

Example two

The present embodiments also provide an alternative implementation of the heating conditions.

In a third alternative embodiment of the heating control method, the heating condition in any of the foregoing embodiments may also be a low-loss operating condition when the first motor is in the start-up state. The control device may inject a heating current into the first motor when the low loss operating condition is satisfied. The heating current may be any of the foregoing embodiments.

Table 10 is an example of a low loss operating condition.

Table 10

In an embodiment of the present application, the operation condition of the first motor may include two operation parameters, namely, a rotational speed and a torque. The low loss condition may be a combination of a set of rotational speeds and torques with corresponding lost heat power below a desired lost heat power threshold. In this embodiment of the present application, as an optional implementation manner, before determining whether the heating condition is satisfied, the control device may collect corresponding loss heating power when the first motor operates under at least two operation conditions, and then determine an operation condition in which the corresponding loss heating power is lower than the expected loss heating power threshold as a low loss condition.

In the embodiment of the present application, various embodiments are described for selecting the desired heat generation power to be lost. For example, an operating condition where the lost heat power is greater than the desired lost heat power threshold may be referred to as a high loss condition. The lost heat power when the first motor is operating in the high loss condition can cause the first motor to trip out of condition in any one of the aforementioned cold conditions during the expected start-up time. For example, when the first motor is operating in a high loss condition, the loss heating power of the first motor is greater than the desired loss heating power. Other optional implementations of determining the low-loss operating mode and selecting the desired loss heating power threshold will be described in detail in other embodiments of the present application, which are not repeated herein.

In embodiments of the present application, the expected loss heating power threshold may also be determined using the following implementation.

In one possible implementation manner for determining the expected loss heating power threshold, the value range of the loss heating power of the first motor includes at least two power intervals which are not overlapped with each other; the expected loss heating power is the maximum power value of the minimum power interval in the at least two power intervals; the combination of the rotating speed and the torque corresponding to the low-loss working condition belongs to the combination value interval of the rotating speed and the torque corresponding to the minimum power interval. The value range of the loss heating power of the first motor is determined according to the value range of the combination of the rotating speed and the torque of the first motor.

As an example, the loss heating power corresponding to different operation conditions is collected in advance, the loss heating power corresponding to different operation conditions is divided according to a distribution rule of power values, and a plurality of power intervals are obtained, wherein the variance between the loss heating power in each power interval and the intermediate value of the power interval is smaller than a deviation threshold. Then, the maximum loss heating power can be equally divided into a plurality of parts, a plurality of power intervals are obtained, and the number of the divisions can be 2, 3 and the like.

In another possible embodiment of determining the expected lost heat power threshold, the expected lost heat power is a maximum lost heat power of the first motor multiplied by an expected heat energy conversion ratio. In one example, the expected thermal energy conversion ratio may be 30%, 50%, etc.

For example, fig. 10 is a schematic diagram of a mapping relationship between an external characteristic curve corresponding to an operation condition of a first motor and a corresponding loss heating power in an embodiment of the present application. The outer characteristic curve of the first motor in the running process can be a curve which changes with the rotating speed according to the power or the torque measured by the first motor in the full-load running process, and the outer envelope curve of the working range of the first motor can be obtained from the outer characteristic curve.

Reference is made to fig. 10, in which the horizontal axis represents rotational speed and the vertical axis represents torque. As an example, the lost heat generation power may be divided into at least two levels according to a distribution of the lost heat generation power. In one example, the lost heat power in fig. 10 may be divided into 3 levels, namely, the lost heat power corresponding to operating condition I, operating condition ii, and operating condition iii, respectively, where I is the lost heat power > ii is the lost heat power > iii.

As an example, since the first motor has a larger loss heat generation near the outer characteristic and a smaller loss heat generation in the inner region away from the outer characteristic, for example, the point loss heat generation power in the operating condition iii is larger than the point loss heat generation power in the operating condition i as shown in fig. 10.

As one example, operating condition I may be selected as the low-loss operating condition.

By adopting the mode, after the first motor is started, whether heating current is injected into the first motor (or the first motor is set to enter a heating mode) can be determined directly according to whether the current operation condition is a low-loss condition, and the real-time loss heating power of the first motor is not required to be calculated in the operation process of the first motor, so that whether the real-time loss heating power of the first motor can enable the first motor to rapidly get rid of the condition of being in a cold state condition is judged.

In the embodiment of the application, the expected loss power threshold value can be implemented in various modes.

In an alternative embodiment of the expected loss heating power threshold, the expected loss heating power threshold may be determined from a difference between a temperature of oil in a vicinity of the first motor and a cold temperature threshold.

As an example, the control device may determine, for each of at least two operation conditions, a corresponding oil temperature change value of each operation condition in unit time, where the oil temperature change value is an increase in temperature of oil in a vicinity of the first motor.

As an example, the control means may also adjust the desired loss heating power threshold according to the temperature of the oil in the vicinity of the first motor. As an example, the control means may set the desired loss heating power threshold to decrease as the temperature of the vicinity of the first motor increases. In practical application, at a first moment after the first motor is started, the expected loss heating power threshold is the maximum loss heating power of the first motor; at a second time after the first time, the desired loss heating power threshold decreases as the temperature of the vicinity of the first motor increases.

In another alternative embodiment of the desired loss heating power threshold, the control means may determine the desired loss heating power threshold based on the temperature of the oil in the vicinity. In practical application, when the first motor is an oil-cooled driving motor, the expected loss heating power threshold of the first motor may be determined according to the temperature of the oil in the vicinity of the first motor; the target operation condition of the first motor is determined according to actual requirements, for example, when the load of the electric automobile is high, the torque required to be provided by the first motor is high, and when the running speed of the electric automobile is high, the rotating speed required to be provided by the first motor is high.

In yet another alternative embodiment of the expected loss heating power threshold, when the first motor is an oil pump motor, the expected loss heating power threshold of the first motor may be determined according to a temperature of oil in a vicinity of the first motor; the target operation condition of the first motor is determined according to actual requirements, for example, when the driving motor of the electric automobile works in a high-loss condition, the heating value of the driving motor is larger, the rotating speed required to be provided by the first motor is higher so as to accelerate the circulation of cooling oil, when the driving motor works in a low-loss condition, the heating value of the driving motor is smaller, the rotating speed required to be provided by the first motor can be smaller, and when the temperature of oil in the adjacent area of the first motor is lower than a cold temperature threshold value, the viscosity of the oil is high, and the first motor is required to generate larger torque to drive the oil.

In the embodiment of the application, the heating condition can be a combination of a cold condition and a low-loss working condition.

As an example, the control means may inject the heating mode current into the first motor when the operating condition of the first motor is a low loss condition and the temperature of the vicinity of the first motor is below a cold temperature threshold. Other embodiments of the present application will be described herein and are not repeated here.

As an example, the control means may inject an energy saving mode current to the first motor when the temperature of the vicinity of the first motor is higher than a high flow rate temperature threshold or the first motor is not operating in a low loss condition. Other embodiments of the present application will be described herein and are not repeated here.

Further technical scheme details and technical effects of embodiments of the present application may be referred to the related descriptions in other embodiments of the present application.

Example III

The embodiment of the application also provides a heating control method. The method is applicable to the heat exchange system in the foregoing embodiment. The execution body of the embodiment of the present application may be a control device, which may be located in the heat exchange system in the foregoing embodiment.

Fig. 11 is a flowchart illustrating a heating control method according to an embodiment of the present application. As shown in fig. 11, the steps of the embodiment of the present application may include:

s301, acquiring a starting instruction of the heat collecting device, and executing S302-1 and S303-1.

Wherein, as an alternative implementation manner, the acquisition of the start-up instruction of the heat collecting device may also be adopted as an alternative implementation manner.

S302-1, when the first motor is in a static state, preheating current is injected into the first motor.

As one example, a warm-up current is injected into the first motor while the first motor is in a stationary state and a cold warm-up condition is satisfied.

S302-2, starting the first motor.

S302-3, when the rotating speed of the first motor is smaller than the high-speed state rotating speed threshold value, heating current is injected into the first motor.

Wherein, as an example, when the rotation speed of the first motor is less than the low-speed state rotation speed threshold, the first heating current is injected into the first motor; and injecting a second heating current into the first motor when the rotating speed of the first motor is larger than the low-speed rotating speed threshold and smaller than the high-speed rotating speed threshold.

S302-4, when the rotating speed of the first motor rises to the high-speed state rotating speed threshold value, energy-saving current is injected into the first motor.

S303-1, starting the second motor, and setting the second motor to operate in a low-loss mode.

Wherein the loss heating of the operating condition of the second motor is below the low loss mode heating power threshold.

As an alternative embodiment, after S303-1, the control device may increase the low-loss mode heating power threshold synchronously as the rotation speed of the first motor increases. The proportion of the rise in the low-loss mode heating power may be in a linear relationship with the proportion of the rise in the rotation speed of the first motor.

S304, when the rotating speed of the first motor rises to the high-speed state rotating speed threshold value, the second motor is set to operate in a high-loss mode.

The heat generated by the second motor is transferred to the heat collecting device through the heat exchanger.

S305, when the temperature of the heat collecting device reaches the target temperature, the second motor is set to operate in a low-loss mode.

By adopting the method provided by the embodiment of the application, in the scene of heating the heat collection device by utilizing the heat of the second motor, firstly, the preheating current is injected into the first motor, so that the temperature of the oil in the adjacent area of the first motor rises above the cold temperature threshold, the first motor can rotate as soon as possible, then, the heating current is injected into the first motor, the oil in the adjacent area of the first motor is continuously heated, so that the oil temperature rises to the peak flow rate, thereby the heat dissipation capacity of the oil cooling circulation loop for cooling the second motor reaches the maximum, in addition, before the oil temperature does not rise to the peak flow rate, the second motor works in the low-loss mode, the problem that the second motor is overheated and burns when the heat dissipation capacity of the oil cooling circulation loop does not reach the maximum, in addition, when the heat dissipation capacity of the oil cooling circulation loop rises along with the oil temperature, the second motor can gradually increase the loss heat generation, or when the heat dissipation capacity of the oil cooling circulation loop reaches the maximum, the second motor can enter the high-loss mode, and the heat collection device can be obtained as soon as possible.

Further technical solution details and technical effects of embodiments of the present application may be referred to the description in other embodiments of the present application.

The heating control method in the embodiment of the application can be applied to single-motor control scenes such as an oil pump motor or an oil cooling motor and the like, and heat exchange system control scenes.

For a single motor control scenario, the heating control method in the embodiment of the application mainly relates to the following processing procedures.

In one aspect, the control device may inject the heating current into the first motor before or after the first motor is started after the start instruction of the first motor is acquired. The mode of injecting heating current into the first motor before starting can be adopted, the control mode of preheating the first motor firstly and then starting the first motor can be realized, and when the temperature of the first motor is lowest, the oil can be preheated firstly, so that the first motor can be quickly separated from a state incapable of rotating.

On the other hand, the control device can determine whether the first motor reaches the heating condition or not according to at least one control decision information such as the temperature of the adjacent area of the first motor, the rotating speed of the first motor or the working condition, and the like, namely, whether the first motor needs to increase heat or not. After it is determined that the heating condition is reached, a heating current is injected into the first motor. The method comprises the steps of determining whether a heating condition is reached according to temperature and rotating speed conditions to determine whether the first motor works in a low-temperature environment, and determining whether the heating condition is reached according to working conditions to determine whether the current heating value of the first motor can enable the temperature of the adjacent area of the first motor to be increased to a required temperature as soon as possible.

In still another aspect, the control means may determine the control target of the heating current for heat increase based on at least one control reference information such as a temperature of a vicinity of the first motor, an operation state of the first motor, a type of the first motor, and the like. Wherein the control target is mainly used for controlling torque and heat energy generated by current injected into the first motor. For example, the target torque and the target rotational speed set in the target operation condition are reduced when the operation state is the locked state, the torque is increased when the operation state is the low speed state, and the target torque is adjusted back when the operation state is the high speed state. In another example, when the first motor is an SPM motor, in the stall state, the quadrature current may be set to zero and the direct current to non-zero. When the first motor is an IPM motor, the magnitude of the heating current may be set to reach the maximum torque in the locked-rotor state and the low-speed state.

For the control scenario of the heat exchange system, the heating control method of the embodiment of the application mainly comprises the following steps: in the heat exchange system, a first motor positioned in an oil pump, a driving motor adopting an oil cooling mode for cooling and a heat collection device needing to be heated are cooperated. Wherein, the control target of the cooperative process includes the following aspects:

On the one hand, the flow velocity of oil in the oil pipeline reaches a high-speed state flow velocity threshold value in a short time, and the temperature overrun of the driving motor is avoided.

On the other hand, the temperature of the heat collecting device reaches the target working temperature in a short time, and the normal operation of the heat collecting device is ensured.

In the embodiment of the application, the oil pump motor assists in heating oil, so as to further improve the circulation rate of the oil pump and accelerate the overall heat dissipation framework for taking out the heat of the driving motor, and the specific implementation mode can be described as follows:

(1) The oil pump does not rotate or has lower rotating speed at low temperature, and the self-heating of the oil pump is increased by the method provided by the invention;

(2) The oil around the oil pump is heated, the viscosity is reduced, and the rotation speed of the oil pump is increased along with the increase;

(3) The circulation of the oil way is quickened, the heat dissipation capacity of the driving motor is strengthened, the driving motor can increase self-heating power, and the oil is further heated;

(4) The rotation speed of the oil pump is further increased, the oil circuit circulation is further accelerated, the heat dissipation of the final driving motor reaches a good state, and the heat carried by the oil heats water through an oil-water heat exchanger;

(5) The cooling water firstly passes through the MCU to absorb the MCU to generate heat, and then the oil heat exchanger absorbs the heat carried out by the oil;

(6) The water after temperature rising flows out of the oil-water heat exchanger and flows into a battery pack cooling water pipeline to heat the battery pack, and the cooling water is cooled;

The water (or cooling water) is a coolant to which an antifreeze is added, and is not particularly limited to pure water or an aqueous solution of a specific component, as long as the cooling function is achieved.

In an embodiment of the present application, as an example, the control device may be located in a control center of the electric vehicle, and the control device may obtain a start control instruction of each component in the electric vehicle.

As an alternative embodiment, before the preheating current is injected into the first motor when the first motor is in the stationary state, it may include: acquiring a start control instruction of a second motor; wherein the second motor is an oil-cooled motor; the first motor is used for driving cooling oil to flow to the second motor through the oil pipeline.

As an alternative embodiment, after the obtaining the start control instruction of the second motor, the method further includes: starting the second motor; controlling the second motor to run in a low heating working condition; the loss heating power of the low heating working condition is smaller than the heating power threshold of the limiting working condition; and the heating power threshold value under the limiting working condition is determined according to the rotating speed of the first motor.

As an alternative embodiment, the method further comprises: when the oil temperature of the cooling oil exceeds a high flow speed temperature threshold value, controlling the second motor to operate under a high heating working condition; the loss heating power of the high heating working condition is larger than the heating power threshold of the limiting working condition; and the heating power threshold value under the limiting working condition is determined according to the rotating speed of the first motor.

As an optional implementation manner, the second motor is a driving motor for driving wheels to rotate in the electric automobile; the electric automobile further includes: a battery; before the obtaining the start control instruction of the second motor, the method further includes: acquiring a starting instruction of the battery; the battery is connected with the downlink oil pipeline through a heat exchanger; the downlink oil pipeline is an oil pipeline between the liquid inlet of the second motor and the liquid inlet of the first motor.

When the vehicle starts and the motor is stationary, the technical scheme provided by the embodiment of the application can be used as a control method for the operation of the oil pump motor, and the method is matched with the oil pump motor immersed in oil at an air gap for use, so that the additional heating oil of the oil pump can be utilized in a low-temperature state, the viscosity of the oil pump is reduced, the rotating speed of the oil pump can be rapidly increased, and circulating cooling oil is normally provided; therefore, the heating capacity of the oil belt motor under the low-temperature starting working condition of the vehicle is improved, and the self-heating efficiency of the motor during low-temperature starting of the vehicle is improved. In addition, in the operation of the oil pump motor, the technical scheme provided by the embodiment of the application can continuously provide additional heat for heating the oil. The technical scheme provided by the embodiment of the application can help to promote the capability of the driving motor to heat the battery pack by promoting the circulation of oil.

Example IV

The embodiment of the application also provides a control device.

Fig. 12 is a schematic structural diagram of a control device according to an embodiment of the present application. As shown in fig. 12, the control device 1200 may include: a processing module 1201, an injection module 1202. As an alternative embodiment, the apparatus 1200 may further include an acquisition module 1203 and a storage module 1204. The obtaining module may be configured to obtain at least one decision information in the foregoing embodiment, for example, a rotation speed of the first motor, a rotation speed of a neighboring area of the first motor, a temperature of the neighboring area of the first motor, an operation condition of the first motor, a loss heating power corresponding to the operation condition of the first motor, and so on. The memory module is used for storing instructions and data.

The processing module is used for injecting heating current into the first motor through the injection module when the cold condition is met;

In an alternative embodiment, the cold condition may include:

The embodiments of the two cold conditions may be combined.

In an alternative embodiment, the processing module is further configured to inject the energy saving current into the first motor through the injection module when the cold condition is not satisfied.

In an alternative embodiment, the energy saving current is a current for enabling the first motor to reach the target operation condition and meet a condition of smaller amplitude, or the energy saving current is a current for enabling the first motor to reach the target operation condition and meet a condition of complete machine mechanical energy conversion energy efficiency.

In an alternative embodiment, the heating current is a first heating current or a second heating current;

In an alternative embodiment, the processing module may be specifically configured to inject the first heating current into the first motor through the injection module when the first motor is in a locked-rotor state; when the first motor is in a locked-rotor state, the first motor is in a starting state, and the rotating speed which can be achieved by the first motor based on the energy-saving current is smaller than or equal to a cold state rotating speed threshold value; the cold state rotating speed threshold value is 0 or the rotating speed which can be reached by the first motor when the oil temperature is equal to the cold state temperature threshold value; the cold state temperature threshold is less than or equal to the preset temperature threshold.

In an alternative embodiment, the processing module is specifically configured to inject the second heating current into the first motor when the first motor is in a low speed state; when the first motor is in a low-speed state, the first motor is in a starting state, and the rotating speed which can be achieved by the first motor based on the energy-saving current is smaller than a high-speed state rotating speed threshold value; the high-speed state rotating speed threshold is a rotating speed which can be reached by the first motor when the oil temperature is greater than or equal to a high-speed state temperature threshold, and the high-speed state temperature threshold is greater than the cold state temperature threshold.

In an alternative embodiment, the first electric machine is an SPM electric machine or an IPM electric machine; the direct-axis current of the corresponding integrated vector current of the first heating current in the dq rotating coordinate system is not 0, and the quadrature-axis current is 0.

In an alternative embodiment, the first motor is an SPM motor;

In an alternative embodiment, the first electric machine is an IPM machine;

In an alternative embodiment, the integrated vector current corresponding to the first heating current in the dq rotation coordinate system is the first vector current; the first vector current satisfies the following control objectives:

wherein the alternating current mode represents that the magnitude of the preheating vector current changes with time.

In an alternative embodiment, in the dq rotating coordinate system, the integrated vector current corresponding to the second heating current in the dq rotating coordinate system is a second vector current; the second vector current satisfies any one of the following control targets:

In an alternative embodiment, the corresponding integrated vector current of the zero torque current in the dq rotational coordinate system is a zero torque vector current; the zero torque vector current meets the following control targets:

In an alternative embodiment, the first motor includes a motor cavity in communication with the oil delivery line; the motor cavity is used for accommodating a stator and a rotor of the first motor; an air gap between a stator and a rotor of the first motor is communicated with the oil pipeline;

In an alternative embodiment, the obtaining module is configured to obtain a start instruction of the second motor before the heating current is injected into the first motor by the injection module; wherein the second motor is an oil-cooled motor; the first motor is used for driving cooling oil to flow to the second motor through an oil pipeline;

The processing module is further used for starting the second motor through the injection module after the starting instruction of the second motor is acquired; and controlling the second motor to operate in a low-loss mode by an injection module;

In an alternative embodiment, the processing module is further configured to control, by the injection module, the second motor to operate in the high-loss mode when the rotational speed of the first motor is greater than or equal to a high-flow-rate rotational speed threshold;

In an alternative embodiment, the obtaining module is further configured to obtain a start instruction of the heat collecting device before obtaining a start control instruction of the second motor;

The second motor is a driving motor for driving wheels in the electric automobile to rotate; the electric automobile further includes: a heat collecting device; the heat collecting device is a battery or cabin heating device; the heat collecting device is in heat exchange connection with the oil pipeline through a heat exchanger; the heat exchanger is located on the oil pipeline from the second motor to the first motor.

Other technical scheme details and technical effects of the embodiments of the present application can be referred to the related descriptions in other embodiments of the present application.

As shown in fig. 13, the embodiment of the application further provides a control device 1300. Wherein, include: processor 1310, interface 1320. In an alternative embodiment, control device 1300 may also include a memory, bus 1360.

In an alternative embodiment, the processor may be configured to implement the functions of the processing module in the foregoing embodiment, and the interface may be configured to implement the functions of the acquisition module and the injection module in the foregoing embodiment.

In one example, the controller may be a control center of an electric vehicle.

In yet another aspect, the present application provides a computer-readable storage medium having instructions stored therein that are executable by one or more processors on a processing circuit. Which when run on a computer causes the computer to perform the method in any of the possible implementations of the first previous embodiment described above.

In a further aspect, a computer program product is provided containing instructions which, when run on a computer, cause the computer to perform the method in any of the possible implementations of the previous embodiments.

In the above embodiments, it may be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the processes or functions in accordance with the present application are produced in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by a wired (e.g., coaxial cable, fiber optic, digital subscriber line), or wireless (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk Solid STATE DISK), etc.

Claims

1. A heating control method, characterized in that the method comprises:

Wherein the first motor is an oil pump motor in an oil pump; the heating current satisfies the following control objectives: when the first motor is in a non-starting state, the heating current is zero torque current, the torque generated by the zero torque current is zero, and when the first motor is in a starting state, the heating current is heating current, and the heating power of the heating current is larger than that of the energy-saving current; or when the first motor is in a starting state, the heating current is a heating current, and the heating power of the heating current is larger than that of an energy-saving current, wherein the energy-saving current is used for enabling the first motor to reach a target operation condition when the oil temperature is larger than a preset temperature threshold value;

wherein the heating current is a first heating current or a second heating current;

When the first motor is in a locked state, the first motor is in a starting state, and the rotating speed reached by the first motor based on the energy-saving current is smaller than or equal to a cold state rotating speed threshold value; the cold state rotating speed threshold value is 0 or the rotating speed of the first motor when the oil temperature is equal to the cold state temperature threshold value; the cold state temperature threshold is smaller than or equal to the preset temperature threshold;

The torque generated by the first heating current is smaller than the torque generated by the energy-saving current.

2. The method of claim 1, wherein the cold condition comprises:

3. The method according to claim 1 or 2, wherein the cold condition comprises:

The operation working condition of the first motor is a low-loss working condition, wherein the loss heating power of the low-loss working condition is smaller than an expected loss heating power threshold; or alternatively

The loss heating power corresponding to the operation condition of the first motor is smaller than the expected loss heating power threshold;

4. A method according to claim 3, characterized in that the method further comprises:

5. The method according to any one of claims 1-2, characterized in that the energy saving current is a current for causing the first motor to reach the target operation condition and to meet a smaller amplitude condition, or the energy saving current is a current for causing the first motor to reach the target operation condition and to meet a complete machine mechanical energy conversion energy efficiency condition.

6. The method of any one of claims 1-2, wherein the heating current is a first heating current or a second heating current;

The proportion of the heating power of the second heating current to the total power of the second heating current is equal to the proportion of the heating power of the energy-saving current to the total power of the energy-saving current, and the total power of the second heating current is larger than the total power of the energy-saving current.

7. The method according to any one of claims 1-2, wherein the magnitude of the integrated vector current corresponding to the first heating current in the dq rotational coordinate system is equal to the magnitude of the integrated vector current corresponding to the energy saving current;

the torque generated by the second heating current is equal to the torque generated by the energy-saving current, and the amplitude of the integrated vector current corresponding to the second heating current in the dq rotating coordinate system is larger than that of the integrated vector current corresponding to the energy-saving current.

8. The method of claim 1, wherein the injecting the heating current into the first motor when the cold condition is satisfied comprises:

when the first motor is in a low-speed state, the first motor is in a starting state, and the rotating speed of the first motor based on the energy-saving current is smaller than a high-speed state rotating speed threshold; the high-speed state rotating speed threshold is the rotating speed of the first motor when the oil temperature is greater than or equal to a high-speed state temperature threshold, and the high-speed state temperature threshold is greater than the cold state temperature threshold.

9. The method according to claim 1 or 8, wherein the first electric machine is an SPM machine or an IPM machine;

10. The method of claim 9, wherein the first motor is an SPM motor;

11. The method of claim 9, wherein the first electric machine is an IPM machine;

the energy-saving vector current is the vector current with the minimum amplitude for generating the target torque;

The second vector current is a vector current that produces a target torque and has a magnitude greater than the energy-saving vector current,

12. The method of claim 9, wherein the corresponding integrated vector current of the first heating current in the dq rotational coordinate system is a first vector current; the first vector current satisfies the following control objectives:

the included angle between the first vector current and the d axis is 0, and the through-flow mode of the first vector current is as follows: a communication mode;

13. The method according to any one of claims 8, 10-11, wherein in the dq rotational coordinate system, the corresponding integrated vector current of the second heating current in the dq rotational coordinate system is a second vector current; the second vector current satisfies any one of the following control targets:

14. The method of any one of claims 1-2, 4, 8, 10-12, wherein the zero torque current corresponds to a combined vector current in a dq rotational coordinate system as a zero torque vector current; the zero torque vector current meets the following control targets:

15. The method of any one of claims 1-2, 4,8, 10-12, wherein the first motor comprises a motor cavity in communication with an oil delivery line; the motor cavity is used for accommodating a stator and a rotor of the first motor; an air gap between a stator and a rotor of the first motor is communicated with the oil pipeline;

16. The method according to any one of claims 1-2, 4, 8, 10-12, comprising, prior to injecting the heating current into the first motor:

Starting the second motor;

controlling the second motor to operate in a low-loss mode;

The loss heating power of the operation working condition of the second motor when the second motor operates in the low-loss mode is smaller than a cold heat dissipation power threshold; the cold heat dissipation power threshold is determined according to a cold rotation speed threshold, wherein the cold rotation speed threshold is the rotation speed of the first motor when the oil temperature reaches the cold temperature threshold, and the cold rotation speed threshold is smaller than or equal to the rotation speed of the first motor when the oil temperature reaches the preset temperature threshold.

17. The method of claim 16, wherein the method further comprises:

the loss heating power of the operation working condition of the second motor when the second motor operates in the high-loss mode is larger than a high-speed state heat dissipation power threshold; the high-speed state heat dissipation power threshold is determined according to a high-speed state rotating speed threshold, and the high-speed state rotating speed threshold is the rotating speed of the first motor when the oil temperature reaches the high-speed state temperature threshold.

18. The method of claim 17, wherein the second motor is a drive motor for driving wheels of an electric vehicle to rotate; the electric automobile further includes: a heat collecting device; the heat collecting device is a battery or cabin heating device; the heat collecting device is in heat exchange connection with the oil pipeline through a heat exchanger; the heat exchanger is positioned on the oil pipeline from the second motor to the first motor;

And acquiring a starting instruction of the heat collecting device.

19. A control apparatus, characterized by comprising: a memory and a processor;

wherein the memory is configured to store instructions and the processor is configured to execute the instructions to implement the method of any of claims 1-18.

20. An oil pump, characterized by comprising: a first motor and a control device, wherein the control device is adapted to perform the method of any of claims 1-18.

21. A heat exchange system, comprising: the device comprises a first motor, a control device, a second motor, an oil pipeline, a heat exchanger and a heat collecting device;

The control device being adapted to perform the method of any one of claims 1-18.

22. The system of claim 21, wherein the heat collection device is: a battery; or cabin heating means.